Commit | Line | Data |
c23184fc |
1 | |
2 | package Class::MOP::Immutable; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
7 | use Class::MOP::Method::Constructor; |
8 | |
9 | use Carp 'confess'; |
10 | use Scalar::Util 'blessed'; |
11 | |
b817e248 |
12 | our $VERSION = '0.02'; |
c23184fc |
13 | our $AUTHORITY = 'cpan:STEVAN'; |
14 | |
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15 | sub new { |
c23184fc |
16 | my ($class, $metaclass, $options) = @_; |
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17 | |
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18 | my $self = bless { |
19 | '$!metaclass' => $metaclass, |
20 | '%!options' => $options, |
21 | '$!immutable_metaclass' => undef, |
22 | } => $class; |
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23 | |
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24 | # NOTE: |
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25 | # we initialize the immutable |
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26 | # version of the metaclass here |
27 | $self->create_immutable_metaclass; |
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28 | |
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29 | return $self; |
30 | } |
31 | |
32 | sub immutable_metaclass { (shift)->{'$!immutable_metaclass'} } |
33 | sub metaclass { (shift)->{'$!metaclass'} } |
34 | sub options { (shift)->{'%!options'} } |
35 | |
36 | sub create_immutable_metaclass { |
37 | my $self = shift; |
38 | |
39 | # NOTE: |
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40 | # The immutable version of the |
c23184fc |
41 | # metaclass is just a anon-class |
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42 | # which shadows the methods |
c23184fc |
43 | # appropriately |
44 | $self->{'$!immutable_metaclass'} = Class::MOP::Class->create_anon_class( |
45 | superclasses => [ blessed($self->metaclass) ], |
46 | methods => $self->create_methods_for_immutable_metaclass, |
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47 | ); |
c23184fc |
48 | } |
49 | |
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50 | |
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51 | my %DEFAULT_METHODS = ( |
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52 | # I don't really understand this, but removing it breaks tests (groditi) |
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53 | meta => sub { |
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54 | my $self = shift; |
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55 | # if it is not blessed, then someone is asking |
c23184fc |
56 | # for the meta of Class::MOP::Class::Immutable |
57 | return Class::MOP::Class->initialize($self) unless blessed($self); |
0ac992ee |
58 | # otherwise, they are asking for the metaclass |
c23184fc |
59 | # which has been made immutable, which is itself |
60 | return $self; |
61 | }, |
d9586da2 |
62 | is_mutable => sub { 0 }, |
63 | is_immutable => sub { 1 }, |
64 | make_immutable => sub { () }, |
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65 | ); |
66 | |
67 | # NOTE: |
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68 | # this will actually convert the |
69 | # existing metaclass to an immutable |
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70 | # version of itself |
71 | sub make_metaclass_immutable { |
72 | my ($self, $metaclass, %options) = @_; |
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73 | |
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74 | $options{inline_accessors} = 1 unless exists $options{inline_accessors}; |
75 | $options{inline_constructor} = 1 unless exists $options{inline_constructor}; |
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76 | $options{inline_destructor} = 0 unless exists $options{inline_destructor}; |
c23184fc |
77 | $options{constructor_name} = 'new' unless exists $options{constructor_name}; |
0ac992ee |
78 | $options{debug} = 0 unless exists $options{debug}; |
79 | |
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80 | if ($options{inline_accessors}) { |
81 | foreach my $attr_name ($metaclass->get_attribute_list) { |
82 | # inline the accessors |
83 | $metaclass->get_attribute($attr_name) |
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84 | ->install_accessors(1); |
85 | } |
c23184fc |
86 | } |
87 | |
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88 | if ($options{inline_constructor}) { |
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89 | my $constructor_class = $options{constructor_class} || 'Class::MOP::Method::Constructor'; |
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90 | $metaclass->add_method( |
91 | $options{constructor_name}, |
92 | $constructor_class->new( |
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93 | options => \%options, |
94 | metaclass => $metaclass, |
c23184fc |
95 | ) |
96 | ) unless $metaclass->has_method($options{constructor_name}); |
0ac992ee |
97 | } |
98 | |
99 | if ($options{inline_destructor}) { |
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100 | (exists $options{destructor_class}) |
101 | || confess "The 'inline_destructor' option is present, but " |
102 | . "no destructor class was specified"; |
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103 | |
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104 | my $destructor_class = $options{destructor_class}; |
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105 | |
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106 | my $destructor = $destructor_class->new( |
107 | options => \%options, |
108 | metaclass => $metaclass, |
109 | ); |
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110 | |
111 | $metaclass->add_method('DESTROY' => $destructor) |
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112 | # NOTE: |
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113 | # we allow the destructor to determine |
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114 | # if it is needed or not, it can perform |
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115 | # all sorts of checks because it has the |
116 | # metaclass instance |
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117 | if $destructor->is_needed; |
0ac992ee |
118 | } |
119 | |
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120 | my $memoized_methods = $self->options->{memoize}; |
121 | foreach my $method_name (keys %{$memoized_methods}) { |
122 | my $type = $memoized_methods->{$method_name}; |
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123 | |
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124 | ($metaclass->can($method_name)) |
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125 | || confess "Could not find the method '$method_name' in " . $metaclass->name; |
126 | |
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127 | if ($type eq 'ARRAY') { |
128 | $metaclass->{'___' . $method_name} = [ $metaclass->$method_name ]; |
129 | } |
130 | elsif ($type eq 'HASH') { |
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131 | $metaclass->{'___' . $method_name} = { $metaclass->$method_name }; |
c23184fc |
132 | } |
133 | elsif ($type eq 'SCALAR') { |
134 | $metaclass->{'___' . $method_name} = $metaclass->$method_name; |
135 | } |
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136 | } |
137 | |
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138 | $metaclass->{'___original_class'} = blessed($metaclass); |
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139 | bless $metaclass => $self->immutable_metaclass->name; |
140 | } |
141 | |
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142 | sub make_metaclass_mutable { |
143 | my ($self, $immutable, %options) = @_; |
144 | |
145 | my $original_class = $immutable->get_mutable_metaclass_name; |
146 | delete $immutable->{'___original_class'} ; |
147 | bless $immutable => $original_class; |
148 | |
149 | my $memoized_methods = $self->options->{memoize}; |
150 | foreach my $method_name (keys %{$memoized_methods}) { |
151 | my $type = $memoized_methods->{$method_name}; |
152 | |
153 | ($immutable->can($method_name)) |
154 | || confess "Could not find the method '$method_name' in " . $immutable->name; |
155 | if ($type eq 'SCALAR' || $type eq 'ARRAY' || $type eq 'HASH' ) { |
156 | delete $immutable->{'___' . $method_name}; |
157 | } |
158 | } |
159 | |
160 | if ($options{inline_destructor} && $immutable->has_method('DESTROY')) { |
161 | $immutable->remove_method('DESTROY') |
162 | if $immutable->get_method('DESTROY')->blessed eq $options{destructor_class}; |
163 | } |
164 | |
b817e248 |
165 | # NOTE: |
166 | # 14:01 <@stevan> nah,. you shouldnt |
167 | # 14:01 <@stevan> they are just inlined |
168 | # 14:01 <@stevan> which is the default in Moose anyway |
169 | # 14:02 <@stevan> and adding new attributes will just DWIM |
170 | # 14:02 <@stevan> and you really cant change an attribute anyway |
171 | # if ($options{inline_accessors}) { |
172 | # foreach my $attr_name ($immutable->get_attribute_list) { |
173 | # my $attr = $immutable->get_attribute($attr_name); |
174 | # $attr->remove_accessors; |
175 | # $attr->install_accessors(0); |
176 | # } |
177 | # } |
178 | |
179 | # 14:26 <@stevan> the only user of ::Method::Constructor is immutable |
180 | # 14:27 <@stevan> if someone uses it outside of immutable,.. they are either: mst or groditi |
181 | # 14:27 <@stevan> so I am not worried |
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182 | $options{constructor_name} = 'new' unless exists $options{constructor_name}; |
183 | if ($options{inline_constructor}) { |
184 | my $constructor_class = $options{constructor_class} || 'Class::MOP::Method::Constructor'; |
185 | $immutable->remove_method( $options{constructor_name} ) |
186 | if $immutable->get_method($options{constructor_name})->blessed eq $constructor_class; |
187 | } |
188 | } |
189 | |
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190 | sub create_methods_for_immutable_metaclass { |
191 | my $self = shift; |
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192 | |
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193 | my %methods = %DEFAULT_METHODS; |
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194 | |
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195 | foreach my $read_only_method (@{$self->options->{read_only}}) { |
196 | my $method = $self->metaclass->meta->find_method_by_name($read_only_method); |
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197 | |
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198 | (defined $method) |
199 | || confess "Could not find the method '$read_only_method' in " . $self->metaclass->name; |
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200 | |
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201 | $methods{$read_only_method} = sub { |
202 | confess "This method is read-only" if scalar @_ > 1; |
203 | goto &{$method->body} |
204 | }; |
205 | } |
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206 | |
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207 | foreach my $cannot_call_method (@{$self->options->{cannot_call}}) { |
208 | $methods{$cannot_call_method} = sub { |
209 | confess "This method ($cannot_call_method) cannot be called on an immutable instance"; |
210 | }; |
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211 | } |
212 | |
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213 | my $memoized_methods = $self->options->{memoize}; |
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214 | foreach my $method_name (keys %{$memoized_methods}) { |
215 | my $type = $memoized_methods->{$method_name}; |
216 | if ($type eq 'ARRAY') { |
217 | $methods{$method_name} = sub { @{$_[0]->{'___' . $method_name}} }; |
218 | } |
219 | elsif ($type eq 'HASH') { |
220 | $methods{$method_name} = sub { %{$_[0]->{'___' . $method_name}} }; |
221 | } |
222 | elsif ($type eq 'SCALAR') { |
223 | $methods{$method_name} = sub { $_[0]->{'___' . $method_name} }; |
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224 | } |
225 | } |
226 | |
227 | $methods{get_mutable_metaclass_name} = sub { (shift)->{'___original_class'} }; |
228 | |
c23184fc |
229 | return \%methods; |
230 | } |
231 | |
232 | 1; |
233 | |
234 | __END__ |
235 | |
236 | =pod |
237 | |
0ac992ee |
238 | =head1 NAME |
c23184fc |
239 | |
240 | Class::MOP::Immutable - A class to transform Class::MOP::Class metaclasses |
241 | |
242 | =head1 SYNOPSIS |
243 | |
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244 | use Class::MOP::Immutable; |
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245 | |
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246 | my $immutable_metaclass = Class::MOP::Immutable->new($metaclass, { |
247 | read_only => [qw/superclasses/], |
248 | cannot_call => [qw/ |
249 | add_method |
250 | alias_method |
251 | remove_method |
252 | add_attribute |
253 | remove_attribute |
254 | add_package_symbol |
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255 | remove_package_symbol |
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256 | /], |
257 | memoize => { |
258 | class_precedence_list => 'ARRAY', |
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259 | compute_all_applicable_attributes => 'ARRAY', |
260 | get_meta_instance => 'SCALAR', |
261 | get_method_map => 'SCALAR', |
96e38ba6 |
262 | } |
0ac992ee |
263 | }); |
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264 | |
265 | $immutable_metaclass->make_metaclass_immutable(@_) |
266 | |
c23184fc |
267 | =head1 DESCRIPTION |
268 | |
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269 | This is basically a module for applying a transformation on a given |
270 | metaclass. Current features include making methods read-only, |
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271 | making methods un-callable and memoizing methods (in a type specific |
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272 | way too). |
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273 | |
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274 | This module is fairly new to the MOP, and quite possibly will be |
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275 | expanded and further generalized as the need arises. |
276 | |
c23184fc |
277 | =head1 METHODS |
278 | |
279 | =over 4 |
280 | |
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281 | =item B<new ($metaclass, \%options)> |
282 | |
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283 | Given a C<$metaclass> and a set of C<%options> this module will |
284 | prepare an immutable version of the C<$metaclass>, which can then |
285 | be applied to the C<$metaclass> using the C<make_metaclass_immutable> |
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286 | method. |
287 | |
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288 | =item B<options> |
289 | |
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290 | Returns the options HASH set in C<new>. |
291 | |
c23184fc |
292 | =item B<metaclass> |
293 | |
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294 | Returns the metaclass set in C<new>. |
295 | |
c23184fc |
296 | =item B<immutable_metaclass> |
297 | |
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298 | Returns the immutable metaclass created within C<new>. |
299 | |
c23184fc |
300 | =back |
301 | |
302 | =over 4 |
303 | |
304 | =item B<create_immutable_metaclass> |
305 | |
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306 | This will create the immutable version of the C<$metaclass>, but will |
307 | not actually change the original metaclass. |
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308 | |
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309 | =item B<create_methods_for_immutable_metaclass> |
310 | |
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311 | This will create all the methods for the immutable metaclass based |
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312 | on the C<%options> passed into C<new>. |
313 | |
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314 | =item B<make_metaclass_immutable (%options)> |
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315 | |
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316 | This will actually change the C<$metaclass> into the immutable version. |
317 | |
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318 | =item B<make_metaclass_mutable (%options)> |
319 | |
320 | This will change the C<$metaclass> into the mutable version by reversing |
321 | the immutable process. C<%options> should be the same options that were |
322 | given to make_metaclass_immutable. |
323 | |
c23184fc |
324 | =back |
325 | |
326 | =head1 AUTHORS |
327 | |
328 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
329 | |
330 | =head1 COPYRIGHT AND LICENSE |
331 | |
2367814a |
332 | Copyright 2006, 2007 by Infinity Interactive, Inc. |
c23184fc |
333 | |
334 | L<http://www.iinteractive.com> |
335 | |
336 | This library is free software; you can redistribute it and/or modify |
0ac992ee |
337 | it under the same terms as Perl itself. |
c23184fc |
338 | |
339 | =cut |